Threading die holder



H. D. PENNINGTON THREADING DIE HOLDER July 14, 1931'.

2 Sheets-Sheet 1 Filed Aug. 5. 1927 INVENTOR I Ju1 14,. 1931. HD ENNINGTN 1,814.492

THREADING DIE HOLDER Filed Aug. 5. 1927 2 Sheets-Sheet 2 NTOR PatentedJuly 14, 1931 UNITED STATES PATENTI' OFFICE.

HARLEY D. PENNING'ION, OF PITTSBURGH, PENNSYLVANIA, ASSIGNOR TO UNITEDENGINEERING & FOUNDRY COMPANY, OF PITTSBURGH, PENNSYLVANIA, A (103-POB-A'IION OF PENNSYLVANIA THREAD-Ins DIE HOLDER Application filed.August 3, 1927. Serial No. 210,302.

This invention relates to threading die holders and is particularlyuseful for die holders employed in threading machines for large sizepipe.

In machines for threading pipe of large diameter the dies are generallyvery heavy. They are usually carried by a pair of holder arms which arepivotally connected to the frame of the threading machine. Someprovision must bemade for separating the holder arms when it is desiredto disengage the threading dies from a pipe. The construction heretoforeemployed has usually comprised a shaft having right and left handthreads thereon, these threads engaging nuts carried by the holder arms.shaft in one direction has been effective for bringing the diestogether,' and rotation thereof in the opposite direction has beeneffective for spreading them apart so as to free the pipe. Thisconstruction is undesirable because it requires considerable effort tomove the heavy holder arms, is slow in operation, and is open to theobjection that accurate setting of the dies is difiicult.

I provide toggle means for moving the dieholder arms. Preferably theholder arms arearranged so as to have crossed portions, and the toggleis connected to these portions. Guide'means are provided for the toggleand the construction is such thatthe parts are in substantial balanceand are easily operated. The toggle arms are preferably so arranged thatthey do not depend upon pivot pins for making their working engagementwith the holder arms. On the contrary, they are arranged to make directbearing engagement with the holder arm structures and thus it is insuredthat the parts will always be returned Rotation of the tending portion 6terminating in a buttress 7.

The lower holder member 4 is forked so as to accommodate the portion 6,the forked portions 8 extending upwardly and uniting to form a buttress9. I

Each buttress is recessed to receive the squared end of a pivot block 10having a stem 11 extending to the outside of the buttress.

Each stem is threaded to receive a holding nut 12, and a spring 13 isinterposed betweenthe nut and the buttress proper. A wedge 1 fitsbetween the pivot block 10 and the buttress, the position of the wedgebeing determined by nuts 15 adjustable along studs 16. By adjusting theposition of the nuts 15 the pivot blocks may be moved toward or awayfrom one another.

The pivot blocks 10 are connected by arms 17 and 18 forminga togglejoint.- The arms 17 and 18 [are loosely coupled to the pivot blocks bypivot pins 19. These pivot pins are smaller than the openings providedtherefor in the toggle links, as shown in Figure 3. This provides adirect bearing between the toggle links and thepivot blocksfor holdingthe buttresses apart. It is when the buttresses are held apart that thethreading dies are in working position. When the toggle is operated todraw the pivot blocks together, the dies are spread apart so as torelease the pipe. At this time pivot pins 19 come into play.

hen the toggle arms are in the straight line position of Figure 1, thatis to say, so as to hold the threading dieportions in their.

workingposition,the arm 17 makes a direct bearing connection with thearm 18. The arm 18 is provided with a bearing portion 20 for thispurpose. The arms are loosely coupled by a pivot pin 21 extendingthrough an enlarged opening in the arm 17 and through ,die holder arms.

openings formed in the skirts 22 on the arm 18. The pivot pin 21 iselongated and passes through links 23 and slide blocks 24. The links 23are connected to an operating lever 25 pivoted to the frame member 2 26.The slide blocks 24 work in guide slots 27. One of the guide slots isformed in the frame member 28. The frame member 28 is secured to bosses29 formed on the frame member 2. Outside the frame-members 2and 28 thepivot pin 21 is provided with washers 30 held in place by cross pins 31.The washers 30 are shown in Figures 2 and 3, but :are omitted fromFigure 1 in the interests of clearness.

When the lever 25 is :in .the solid line position of Figure l, thethreading dies are in their-operative position. The :togglearms 1.7 and18 lie in a substantially straight lineand "therefore form an unyieldingbrace for the V The positionof the arms is determined by the slideblocks 24 when they engagethe ends ofthe slots 27. The dies may beadjusted by shifting the wedges 14 until the dies members occupy thedesired position. Thereafter the toggle maybe operated as of ten asdesired and the dies will always be returnedto the same position.

When the lever 25 is pulled down to the chain line position of Figure 1,the toggle arms occupy the position indicated in chain lines. This drawsthe buttresses 7 and 9 .together and spreads the die members D apart.The opening movement just described is limited by the engagement of theslide blocks 24 with the ends of the slots 27.

The die may be opened and closed very rapidly and is always moved to thesame position on successive operations. By reason of the fact that thetoggle arms are loosely coupled and directly engage the die holderstructures, there is no chance of lost motion.

The arms 3 and 4 substantially balance one another .and the holdertherefore operates smoothly.

Figure 4 shows a different form of structure, wherein partscorresponding to similar parts in Figures 1 to 3 have been given thesame reference character with an a suiiiXed thereto. In this form of theinvention, the toggle arms 17aand 18a make direct bearing on thebuttresses 7a and 9a. The buttresses are provided with cars 40 forholding pins 1941. These pins are loosely fitted so as to insure directbearing of the toggle arms .on the buttresses when the parts are movedto operative position.

The toggle arms 17 a and 18a are connected through a pin 41 to an arm42. The arm 42 is connected through a pin 43 to an arm 44. The arms 42and 44 constitute a second toggle. The arm 44 is rotatably mounted on arockshaft 45 carrying an operating lever 46. When the operating lever isin the position shown, the toggle arms 42 and 44 lie in sub Stantially astraight line and hold the threading dies in their working position.When the operating lever 46 is moved downwardly, the buttresses 7 a and9a are drawn together so as to open the die.

The pin 41 is carried by a slide 47 working in a frame member 48. Therock-shaft 45 is also carried in a slide 49. The slide 49 maybead-justed to differentpositions in the frame member 48 by means of.ascrew .50 having a locking nut 51. If Eit .is :desired to set the diesa' little closer together, the .block 49 is moved to the left, as viewedin Figure 4. This causes the toggle arms 17a and 18a to assume a morenearly straight line position uponclosing of :the die. If it is desiredthat the final setting of the die members shall be a little furtherapart, the screw 50 is operated to adjust the block 49 to the right. Astop '52 is'pro-v'ided in the frame 48.. This stop bears against the.arm 44 when it is in arm regardless ofthe positionofthe block 49.

The construction shown in Figure 4 possesses allof-the advantagesioftheform shown in Figures 1 to '3, and has the further .ad-

for adjusting the mechanism of Figures 1 to '3 is eliminated and asingle adjusting meansseciuedtothe frame is substituted. In either case,the toggle arms, reason of the loose pin connections, are so formed as"to' 1. A threading die holder comprising a frame, a ,pair of holdermembers carried by the frame, a toggle connecting the holder members, apivoftpin connecting the arms of the toggles, guide blocks on said pinand means engaging said blocks for guiding the pivotpin in the-frame. iV i i '2. A threading die "holder comprising a pair of holder members,the holder members "being ,pivota-lily mounteda-nd extending .hori-'zontal-ly from such pivotal mounting, .the holder members having.crossed portions, a toggle connected to such portions, "the ,tog 'lehaving a horizontally movable pivot an a support for the pivot.

3. The combination with die holders pivotally connectedand havingcrossed opposing buttresses, of an extensible toggle-mechanismcomprising a pair of substantially straight pivoted toggle arms, pivotblocks at the ends of said arms for engagement with said buttresses, themounting of .said' blocks and arms on their pivots being loose so thatforce may be transmitted directly therebetween without stressing thepivots, and means the working position. 'It cooperates with the 9.vantage that the blocks and keys employed for extending said arms toclamp said holders together.

4. A threading die holder comprising a pair of holder members which arepivoted at one extremity and have crossed buttress extensions at theiropposite extremities, and toggle mechanism for opening and closing saidmembers including a pair of extensible toggle arms which are pivoted atone extremity at a common operating point and at their oppositeextremities have a pivotal connection with relation to said buttressextensions, a clearance space being provided around each pivotalconnection so that the bearing pressure is applied directly to said armsinstead of the pivots when the arms are extended to move the holdermembers to closed position.

5. A die holder comprising a pair of pivoted die-holding members formedwith crossed extensions, and toggle mechanism for opening and closingsaid members comprising a pair of substantially straight extensibletoggle arms which are pivotally connected at one extremity at a commonoperating point and at their opposite extremities are pivotallyconnected to said extensions.

6. A die holder comprising a pair of pivoted die-holding members formedwith crossed extensions, and toggle mechanism for opening and closingsaid members comprising a pair of substantially straight extensibletoggle arms which are connected at one extremity to a common pivotalconnection and at their opposite extremities are provided with pivotblocks which engage said extensions, a guide block for said commonpivotal connection, and lever means for operating said toggle mechanism.

In testimony whereof I have hereunto set my hand.

HARLEY D. PENNINGTON.

